Edge collectors or optical waveguides are used for collection and concentration of light; in particular, sunlight. An edge collector or optical waveguide is defined for this application as an optical device that receives light from a top surface, and delivers the concentrated energy to the edge of the device. FIG. 1a shows a simple schematic of the cross section of an optical waveguide 10. FIG. 1b is a 3D representation of the same optical waveguide 10.
In practice, these types of optical waveguides 10 are generally of the type described in U.S. Pat. Nos. 7,664,350 and 7,672,549. Other types of optical waveguides include luminescent solar concentrators, or dye luminescent solar concentrators. FIG. 1c shows an optical system of the former type. Input light 20 falls on multiple concentrating units 40 across the aperture, and the waveguide 10 collects the concentrated light from all the units and delivers it to an edge 30 of waveguide 10.
However, there are many advantages to having a secondary set of optics 50 (see FIGS. 2 and 3a) at the edge 30 to redirect the light 20 in a favorable manner. In FIG. 2, the light 20 is delivered to the edge 30 of the waveguide 10 and is redirected approximately 90 degrees towards a receiver 60 placed parallel to the base of the waveguide 10. The invention articulated herein describes a variety of methods to design these secondary redirecting optics 50. The invention helps make the optical waveguide 10 more useful. Key commercial criteria for the optical waveguide concentrating systems include compactness, efficiency, level of concentration, and manufacturability. Different methods for the redirection impact these criteria in different ways.
It should also be noted that the applications for this optical waveguide 10 or device are several. The light energy can be delivered to a variety of receivers. FIGS. 3a to 3d show some examples of receivers 60, including further concentrating or diffusing optics such as lenses, compound parabolic concentrating optics, photovoltaic cells, or heat exchangers which will be described in more detail hereinafter.